It doesn't make much sense and it's extremely difficult for me to understand for some reason... I think he's quoting a movie/diary/book that has to do with flight... something about Yuri Gagarin (the first "cosmonaut"... and then more about how he's getting ready for his first flight bla bla.
After he jumped I think he was like swearing and taunting the people on the balconies or smth weird-ass like that.
The talking annoyed me honestly.. I wish he had just jumped like 1 minute and 30 seconds earlier.